Purification of fluids by means in a settling tank of magnetic separation



Malh 2, 1954 w. F. EGLOFF ETAL 2,670,847

PuRIEIcATIoN oE ELuIns BY MEANs IN A sETTLING TANK 0E MAGNETIC SEPARATION March 2, 1954 w. F. EGLOFF ETAL 2,670,847

PURIFICATION OF FLUIDS BY MEANS IN A SETTLING TANK OF MAGNETIC SEPARATION Filed March 3, 1951 `4 Sheets-Sheet 2 i. Sl R l? m@ March 2, 1954 W EGLOFF ErAL 2,670,847

PURIFICATION OF FLUIDS BY MEANS IN A SETTLING TANK OF MAGNETIC SEPARATION v Filed March 3, 1951 4 Sheets-Sheet 5 GLoFF ET AL 2,670,847 IDS B IN A SETTLING TroN March 2, 1954 l W, F E

l PURIFICATION OF FLU Y MEANS TANK OF MAGNETIC SEPARA 4 Sheets-Sheet 4 Filed March 3, 1951 NNY Patented Mar. 2, 1954 PURIFICATION OF FLUIDS BY MEANS IN A SETTLING TANK F MAGNETIC SEPARA- TION William F. Eglol and Kenneth E. Yates, Syracuse, N. Y., assignors to United States Hoffman Machinery Corporation poration of Delaware New York, N. Y., a cor- Application March 3, 19'51, Serial No. 213,707

1 Claim. l This invention relates to the purification of uids and more particularly to the removal of metal chips and abrasive particles from coolant used in abrading operations. Such removal has heretofore been accomplished by passing the used coolant through settling tanks and filtering apparatus before returning it to the cutting or abrading tool for reuse. Magnetic separators have also been used for the same purpose.

While good results as regards purification have been attained in the use of the former type of apparatus, so long as the filters were maintained in good Working condition, a practical disadvantage lies in the fact that the filter surfaces soon become clogged and removal of the :filter cake collected thereon becomes necessary at somewhat frequent intervals, by alternating a filtering cycle with a backwashing cycle, during the latter cycle the filter cake is removed and deposited as sludge in .the bottom of the settling tank. On the other hand, such magnetic separators as have been used for the removal of metal and abrasive particles from soiled coolant have relied almost entirely upon their magnetic action and have not incorporated the separator devices in apparatus wherein proper provision was made for the settling out of the coolant of the coarser particles of metal and abrasive material. As an example of the tank settling and filtering procedure and construction reference may be had to the coolant iilter system disclosed in United States Patent 2,494,534. The general operation of a magnetic separator for coolants may be found in United States Patent 2,466,839. One of the objects of the present invention is to provide apparatus adapted to attain more eficient coolant vtreatment in a simple and practical4 ysystem embodying settling arrangements whereby coarser abrasive material and magnetic metallic particles are eiectively removed and which system additionally includes an improved magnetic unit, especially arranged and adapted to the elimination of such iine metallic particles as have a tendency to remain in suspension in the fluid and conseouently are not removed by settling alone. A further object is to provide means to control the rate of flow of the coolant through the settling tank to the area where magnetic attraction 'of the unit becomes operable upon -the suspendedV magnetic content of the coolant. A further object is to provide an improved form of magnetic unit for cooperative use within' a 4settling tank and to further provide for the lpractical location of such unit Within said tank,I Other objects will be in part obvious 'and in partpointed outhereinafter.y l A The invention accordingly consists in the feal vtively described herein, and the scope of the api plication of which Will be indicated in the following claim.

In the drawingsj Fig. 1 is a plan view of one embodiment ofthe invention; comprising a separator tank and magnetic unit;

Fig. 2 is a vertical section taken substantially on line 2-2 of Fig. 1;

Fig, 3 is a slightly enlarged fragmentary cross section of the iiight Wiper assembly taken on line 3-3 of Fig. 1; Y

Fig. 4 is a view` similar to Fig. 3 showing the iinal point of scraping or wiping action in respect to a conveyor iiight member; Y

Fig. 5 is a left end view of the invention as shown in Fig. l; the left end wall of the `tank b eing omitted and portions of the side and bottom walls being shown in cross-section; n Y l Fig. 6 is an enlarged front elevation of the magnetic separator unit embodied in the appa` ratus as shown in Figs. 1 and 2 with a section of the front plate cut away;

Fig. 7 is a vertical cross section taken l-'l of Fig. 6;

Fig. 8 is a diagrammatic view of a closed coolant purification system.

As conducive to a clearer understanding of the invention it should be understood that with cutting and grinding tools it is common practicev to supply a coolant in .the form of a stream of' liquid, such as an oil emulsion, which flows onto the tool and the work during the working'operation. This coolant carries away from the work small particles of metal and, during a grinding' operation, small particles of the grinding wheel (referred to as emery). As Will be readily seen,` it is important to remove such particles of emery and metal from the coolant in order to avoid? scratching the iinished surfaces of the parts treated in the machine` tool.

In the illustrated embodiment of the invention the supply of coolant is heldin a horizontal tank having disposed adjacent one end a magneticl separator unit assembly, about and through which the coolant flows in its passage from the inflow to the outflow pipes of the tank, which conduct the coolant from and'to an associated' machine tool.

on line At the end of the tank vopposite thev separatorunit, the end wall of the tankfis inclined, 4and a slow-moving endless V.chain con-i;

veyor, comprising a drag arrangement, continuously clears the front surface of the magnetic unit of collected particles of metal and also continuously removes sludge containing both metallic and emery particles, from the bottom of' the tank, to discharge the sludge over the top of the inclined wall into any suitable receptacle.

A pump means causes the coolant to ilow from the tank after its passage through themagnetic unit to the machine tool, from which it is re\ turned by means of the inow or return conduit to the tank for purication.. Valves. placed. in the inow and outow linea, control, thee ratel of ow of the coolant through` the system,. whereby the period of time required for the influent coolant to pass to the operative area oi the. magnet. unit may be nicely determined. The period oi detention in the tank will vary with the size. and; capacity of the system and with the viscosity of the. coolant. employed. In practice. these detentionperiods vary. between, threeV and nveminutes.

The magneticY plate comprises the front face i a. fluid tighty nonc-corrodible. box. in` which are incorporated aV group. or groups. of permanentmagnets, as will be described. later.

Referring toA Figs. L andl 2. of. the drawings., an open-topped horizontalv rectangular tank 2, hasiat the left or rear end (Fig. 2), aninolinedendv wall 4, and. atthe; right, an. upright. end; wall 6. The box-likemagnetic separator unit. 8 is supported upon the side walls of the tank by angle brackets` Mh. in such spaced relation to, thel wall: 6- as to leave between the wall 6 and thefront. face. L2 of theunit a; iieldof magnetic attraction lli; The brackets Ml-restuponv suitable anglemembers i preferably welded upon the side walls It andl 2t' oi?` theA tank GFigs.. 1-, 2. and*` 5)..

'Ilhe magnetic. separator unit- 8 comprises a rectangular box-like structure, upontwosides ofw-hichthe brackets Il)` are mounted.. rIfhe front face of thebox.unitisamagnetio plate. 22,. whichy ishermeticallysealed' in' contact with the.y front edges of the bon structure; A-tftop.- and bottom of the front face, rearwardly incl-ined' surtaces arefprov-ided, asA at 2k andi 2-6- (Fig. 7) to, facilitate the passage:thereover. of the wiper flights ot the sludge conveyor hereinbeforementioned.` Some what above. the center ot the magnetic plate 22 and centrally disposed with respect tothe sides-1 of. the unit', the` plate is provided w'nh a circular opening 28 (see Figs. 6 and 7:)i of. relatively largesize; as for' example: 4 inches. Birectly opposite this. opening a smallerV openingI 3191' is providedA in the-rear wall 32- of` the unit. Mounted. in sealed relation tor these openings iszatunnel-shaped reducingmemberA 34 which extends rearwardly of the opening 30, wheref it is connected to a pipe: nipple 3611 The reducerv 34- is; supportedwithin. the box-like unitV structure bytwo suitable par titions 3d andi40 composed' preferably of plywood,v which iittightly about'` they member 34 and are inl close contact at their edges*Y with the interiors ofthe sidewalls of the unit., Suitable brackets oral-ips- 42 are employedY to-Inountthe plywood partitions and the reducer member in subs-tairtially; rigid relation to thev saidf unitr walls;

Ai plurality of'openings as Mv arey formed in: the partition 3B: in: a selected geometrical: arrangement. about; the exit. passage formed by the` funnel 34f and'` each. of: these openings-r is= set the nortlr and southpoles= of ai horseshoe shapeds permanent magnet; 46 of, high: permeability. The severa-l magnets areY so arrangedv as: tot bring` poles: et op posite polarity of adjacent magnets in suitable: nearnessito. each othemwhereby: poles' otthe polarity are disposed remotely from one another. These magnets serve to set up magnetic fields in the magnetizable sheet or plate 22 which iields extend. their attractionv through a. considerable portion of the space in frontv of said plate,.where by a high percentage of the magnetic particles entrained in the coolant are attracted to the face of the magnetic plate as the coolant flows around the. sides. of.' the unit to the front side of the discharge conduit34`. rEhe said magnets are rmly held in their chosen positions by the plywood forms and suchforrnsare held in their positions by clipsl 42. The coolant fluid level is constantly maintained-,approximately one inch below the top oi: thea separator unit, as indicated at 48 in Fig. 2.

The dirty coolant enters the tank 2 in the zone over the inclinedl end wall 4 through a pipe 5U having a. rearwardly and downwardly turned outlet E2. Suitable baie walls 53 and 54 direct the coolant toward the front or right.- end ot the tank as seen in the figures. Battles 53.- and 54 extendl between the tank sidewalls I8. and to which, the. baiiies are welded. The incoming coolant isithus.- directed by the baflies towardl the. separator unitabout which it passes on: its, way to. the mouth' 23 of the.V discharge conduit. 34. During the slow movement of. the unagitated; coolanttov the dischargev the` heavier particlesV of both emery andi metal settle to the bottomf of the tank, while nearly alll finer particlesiofmetat still suspended. inthe emulsionarev drawn toandV collect. upon the. magneticl pla-te.

The iiow of coolant. through and out ofv theA tank and unit is largely dueto theoperation ot a;A centrifuga-l or other pump, 56 which connects. onV its suction side by means of a pipe' 58a and a piper 66 supported within thetank with the sepa-ratei" dischargenippleI 35'. Thel pipe; (i0l extends'. acrossthe tank trom side to sideand maybe connected tothe discharge pump at either end,. the unusede endbeing capped1 or closed with a'. suitable Plug:

A valve 62f is connected inthe discharge line` ES--tilY anda valve 64; inthe coolant admission line The discharge side of the pump.` is, as indicated in Fig. 8, connected to deliver: clean. coolant toY a machine to@ a machine toolI 61 the return` line 86 from which connects through` any suitablev delivery pump- 58l and:` controlk valve: E43. with the inflow pipe 50 of theY separator tank.

The metal particles which have been colf' lectedA upon the magnetic plate of the separaten unit and the sludge colleted on the sloping sidet andbottomy of the tank are removed` by an@ endless chain conveyor or wiper assembly formed'. by two endless chains 1.2 and anumber'of spaced Scrapers or' flights 1.4', each of which comprise' a plate wiper` 'l5v and a tank bottom. wiper 't6'. These wipers aremade in the form ofV a pair of'. large and' small angle irons wel'd'ed back to bacls:` and securedf as bywelding` nearthe endz of each. pair: tov a link of the two conveyor chains 12.. Each chain extends ('Fig. 2) around upper' and lower idler' sprocketv wheels 'lf at' the right end' of the tank, along ther bottom oi the' tank tot another idler sprocket wheel' 8D", disposed adijacent thev angle" formed' bythe meeting. of the bottom of the tank with the inclinedl endl; up the slanting endwall of the tank. to' a drivesprocket wheel` 82 and then to the right to the upper sprocket wheel 'I3- Each pair of sprocket wheels. is mounted on a shaft (see Fig. l) which is supported at' the two sides' of the tank; Sprocket. Wheels 82 haveY a shaft 84 which is driven atone: @11d through a belt. 8% by a motor. operal tion, the iiights 'I5 are moved slowly downwardly in wiping contact with the outer surface of magnetic plate l2. The metallic sludge removed thereby is deposited in the path of the wiper members I6 which move slowly along the bottom of the tank and up the wall 4. At the top of the end wall 4 the sludge collected or carried by each ilight is scraped downwardly off the same, as indicated in Figs. 3 and 4, to be discharged beyond the top of the end wall into a suitable sludge chute 90, beneath which any portable catch receptacle may be placed.

One of the advantages attending the use of the disclosed magnetic separator unit in a sludge settling tank, in place of the ordinary pressure filter, is that practically no service maintenance is required, as previously experienced by the users of filters with regard to screen cleaning and the changing of lter papers, bags or cartridges. Further, it will be seen that the use of the magnetic separator unit in connection with a pressure ilter should also increase the efficiency of the iilter, as by installing the magnetic unit ahead of pressure filters and removing the bulk of the solids prior to filtration.

Tests made under varying conditions employing the separator assembly described have resulted in a percentage removal of solids from the coolant of from 75 to 90 per cent.

As many possible embodiments may be made of the mechanical features of the above invention without departing from the scope of the invention,'it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

We claim:

In apparatus for removing entrained magnetic particles from a liquid of the nature described, in combination, an elongated horizontal tank adapted to contain a supply of said liquid and having at one end an upright wail, a box-like separator unit supported in spaced relation to said upright wall below the normal liquid level in said tank and comprising a magnetic plate facing said upright wall, inlet means disposed to deliver used liquid to said tank at a point remote from said magnetic unit, discharge means passing horizontally through said magnetic unit including said magnetic plate, adapted to permit removal of liquid from the space between said upright wall and said plate, means adapted to withdraw liquid from the said space through said conduit and maintain a flow of liquid within said tank from said inlet to said discharge means at a known rate, and means operable constantly to remove adhering, magnetic particles from said magnetic plate.

WILLIAM F. EGLOFF. KENNETH E. YATES.

Armstrong et al. Jan. 17, 1950 

